How big is the rib-eye portion? If the rib-eye sandwich is around 1/3 pound, then you might want to allot 1/4 pound of potatoes each. Most folks feel absolutely stuffed with a full 1/2 pound of food in them. I would probably look at 1/3 pound of finished product per man.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."